Storage container for night storage air heater

ABSTRACT

crystallization, a plurality of air channels through which ambient air may flow formed in part by said panel, and an electrical resistance element for heating said material during periods of low tariff, characterized in that said heater is in the form of a sheet, in that said panel has a plurality of depressions formed thereon where said depressions extend in the direction and form on one side of the panel a part of said air channels and on the other side of the panel a part of said chambers with the chambers alternating with the air passages, and in that the panel has a flat flanged strip extending along two sides thereof sealingly connected to said oppositely disposed wall member.

United States Patent [1 1 Laing 1 STORAGE CONTAINER FOR NIGHT STORAGE AIR HEATER [76] Inventor: Nikolaus Laing, l-lofener Weg 33-37,

Aldingen near Stuttgart, Germany 22 Filed: oa. 28, 1970 21 Appl. No.1 84,732

[30] Foreign Application Priority Data Nov. 4, 1969 Austria A 10.335/69 [52] US. 219/378, 165/104, 165/166, 219/365 [51] Int. Cl. F24h 7/02, F28d 13/00, F28f 3/04 [58] Field of Search 219/365, 378; 165/104, 166

[56] References Cited UNITED STATES PATENTS 1,840,598 l/1932 Murray 219/365 X [451 July 3,1973

1,054,409 2/1913 Harrison et al. 219/365 1,796,317 3/1931 Bennett 219/365 X 3,356.828 12/1967 Furness 219/378 X FOREIGN PATENTS OR APPLICATIONS 643,121 3/1937 Germany 165/104 Primary Examiner-R. F. Staubly An0rneyPennie, Edmonds, Morton, Taylor & Adams [57] ABSTRACT Storage container for electric heaters storing heat in form of crystallization energy and comprising panels which have prismatically shaped bulges arranged parallel to air channels and being disposed opposite each other in such way that cavities are formed for receiving the storage mass.

14 Claims, 19 Drawing Figures Patented July 3, 1973 4 Sheets-Sheet 1 Patented July 3, 1973 4 Sheets-Shoot 3 Patented July 3, 1973 3,743,782

4 Sheets-Sheet 3 Patented July 3, 1973 4 Sheets-Sheet 4 STORAGE CONTAINER FOR NIGHT STORAGE AIR HEATER DESCRIPTION OF THE INVENTION The invention relates to night space storage heaters, in which the thermal energy is stored during the night by melting of suitable storage masses which preferably have a temperature of crystallization below the temperature of carbonization. The temperature of carbonization is that temperature above which the particles of dust present in the ambient air disintegrate and emit an odor. By using low temperatures of crystallization, the insulating layers, which in the case of conventional night storage heaters occupy the major part of the overall volume, become of negligible thickness and may as a rule be dispensed with altogether. The advantage attendant upon the use of low temperatures of crystallization is however counteracted by the disadvantage that the walls of the storage vessel through which the heating current passes and which are in contact with the ambient air so as to give off the stored heat, need to have a very large surface since the natural gradient to the temperature of the ambient air is correspondingly low. In view of these large areas, the storage vessels can only be constructed of very thin walls, since the ratio of the wall material to the storage mass is otherwise disproportionately large. Where non-metalic materials for storage are used, poor thermal conductivity becomes a problem so that it becomes advantageous to use a thinwall construction for the container. However a high degree of rigidity of the storage containers is required from the point of view of adequate thermal contact with the heating elements. For statical reasons also a degree of rigidity is necessary which permits the storage bodies to be self-supportingly erected or suspended.

The invention relates to economical constructions of and manufacturing processes for storage containers which meet the requirements of minimizing the amount of material used, whilst providing surfaces of adequate size facing air channels. The invention also take into account that, from the point of view of the danger of egress of molten storage mass and ingress of air to the storage mass, seams which communicate with the outside should be of minimum overall length, in order to reduce the probability of leakage to the outside to a minimum.

The invention solves the problem, i.e.

a large container surface facing air channels,

minimum wall thickness,

high rigidity,

minimum seam length, by assembling panels with shaped bulges into plateshaped hollow bodies, which receive the storage mass within them and enclose the air channels between them. Panels of this kind have seams on only three or four external edges, whilst none of the other scams communicate with the ambient air and therefore present no danger. By means of both the bulges and/or corrugations, the storage bodies in accordance with the invention become so rigid that they can be pressed together with the heating elements utilized to heat the storage mass. The heating elements are pressed against the storage containers by means of resilient components, so that a secure juxtaposition for the avoidance of heat radiation is ensured over the entire surface of the storage bodies provided. The resilient components proposed by the invention are mats ofa material of rubber-like elasticity or also metal felts or panels of resilient metal, e.g. hard aluminum. In place of two panels with bulges, one panel may also be provided which is bent about a folding axis and which is sealed only at the axial ends and, if desired, at the edge opposite the folding axis, e.g. by welding. In this case the heating element may also be arranged in the central plane, but it must be protected against attack by the storage mass.

The invention will be described with reference to the drawings.

FIGS. 1 and 2 show a storage insert formed of like deep-drawn panels, in section and perspective views respectively.

FIG. 3a is an end view of a panel illustrated in FIG. 1.

FIG. 3b is a plan view of the panel shown in FIG. 3a. FIG. 4 shows a cross-section through a different arrangement whilst using the same shaped parts.

FIGS. 5 and 6 show heating elements to an enlarged scale.

FIG. 7a is an end view of a further embodiment of a storage container.

FIG. 7b is a view similar to FIG. 7a illustrating the container after it has been folded.

FIG. 8a is a cross-sectional view of a heat storage oven having a further embodiment of a container.

FIG. 8b is an enlarged section of a portion of FIG. 8a illustrating a heating element.

FIG. 9a is an enlarged end view of the storage container illustrated in FIG. 8a.

FIG. 9b is a plan view of the container illustrated in FIG. 9a.

FIG. 10a is a perspective view of corrugated panel used in a still further embodiment of a storage container.

FIG. 10b illustrates the panel of FIG. 10a after being folded into an undulating shape.

FIG. 10c illustrates the panel of FIG. 1% when squeezed in the corrugated region.

FIG. 10d is an enlarged view of a portion of the panel of FIG. 10c illustrating portions of the panel prior to and after the corrugated region has been squeezed together.

FIG. l0e is a view of the panel after it has been folded to form a container to enclose the storage mass.

FIG. 11 is an enlarged section of FIG. l0e taken along line X-X illustrating the means for closing that end of the container formed in FIG. l0e.

FIGS. 10 and 11 show manufacturing steps and parts of the heating body made from a folded panel.

FIG. 1 shows a horizontal section through the insert of a night storage space heater, comprising of two like storage elements and a sheet-like heating element therebetween. The storage element comprise of three like sheet metal panels, inwhich bulges I are produced by a deep drawing process. The circumferential seam 2 is made up ofa flat flanged strip along two of the sides of two of the panels and is produced by roller seam welding the strips together, whilst the bridges 3 lying in the plane of origin are connected together by spot welds 4. The bulges I have corrugations 5, by means of which on the one hand the volume of the individual storage containers or chambers 6 and to the same extent the surface of the air channels 7 is enlarged, whilst the hydraulic radius which determines the natural convection is not correspondingly reduced. Where two of the panels having bulges are connected together along their flat flanged strips, one panel becomes an oppositely disposed wall member with respect to the other panel such that the bulges of each panel together form an individual storage container 6.

Towards the heating element 7, the space for accommodating the storage mass 6' is bounded by a sheet metal panel 8 which is connected by a roller seam weld 2 and a spot weld 4' with the bulged panels in like manner. Panel 8 comprises a wall member which is oppositely disposed to the panel having the bulges. The heating current flows through the sheet metal walls 1, 1 as well as through the storage mass 6, whose largest cross-section faces the heating element 7 which is in the form of a sheet. The two storage element which between them enclose the heating element 8 are pressed together by brackets 9, so that the heating element 7 is uniformly pressed against the sheet metal panels 8. Channels 10 are provided in the vicinity of the upper boundary, through which the adjacent storage mass spaces or chambers 6 and 6" communicate. Filling takes place by providing the circumferential edge 2 with apertures at the level of the channels 10, the storage mass being filled in through these apertures at one end, whilst the air escapes at the other end where this filling takes place. FIG. 2 shows a side view of the storage insert in accordance with FIG. 1. The overall length 11 is so chosen that the insert can be carried by one person and inserted into a housing.

FIG. 3 shows a plan and side view of deep drawn sheet metal panels for a storage insert according to FIG. 1. Folds 30 are provided between the bulges 1, whereby a greater depth 31 of the bulges can be achieved for a given amount of stretching. The edge strip 32 shown cross-hatched, is severed along the section line 33.

FIG. 4 shows a storage insert using storage elements similar to those in FIG. 1, but in which the heating element 40 is in the form of a sheet-like heating foil, which is inserted between the interlaced bulges 41 and 41.

FIG; shows to an enlarged scale the region marked by the circle 12 in FIG. 1. Between the sheet metal panels 8 and 8 insulating foils 50, 50 are provided on whose internal sides undulating metal layers 51 are arranged preferably by vapor deposition of metal layers. These heat producing metal layers 51 are interrupted for the purpose of increasing the resistance only where heat is withdrawn from the heating element, whilst they are continuous between the storage containers in the -zone 13 (FIG. 1) and thereby generate only a small amount of heat. The two insulating foils enclose between them a mat 52 of silicon foam rubber, which causes the insulating foil 50 to lie uniformly against the sheet metal panels 8.

FIG. 6 shows the same construction as FIG. 5, but the insulating foil 50 is insulated towards the inside by means of an uncoated insulating foil 61 and a mat 62 consisting of thin resilient metal wires is formed.

FIG. 7 shows two process steps for the manufacture of storage bodies comprising of two sheet metal panels 70, 70. After the bulges 71 have been produced, the panels are connected together along the seam 72, and thereafter folded along the edges 73. The air channel 74 has arched portions 75 which result in a region of large hydraulic cross-section.

FIG. 8 shows a horizontal sectionthrough a storage oven and a plan of the storage insert. The rear wall of the storage oven is united with the wall of the room 81. A thin insulating layer 82 is provided therebetween. The storage elements 83 are in the form of flat, undulating hollow bodies, which enclose between them triangular air channels 84. Between the inwardly directed backs 85, the heating element, which consists of a sheet-like heating foil 86 coated on both sides, two insulating foils 87, 87 and two aluminum panels 88, 88 is clamped by bending it into an undulating shape. The fins 89 protrude into the air channels 84. The heating element is everywhere contiguous to either the back or the opposite back 85. The aluminum sheets 88, 88' may also be used to form the outer boundary 88", 89", whereby the heat emission is improved. The storage elements 83 and 83' are relatively stressed by means of a resilient steel wire 90.

FIG. 9 shows to an enlarged scale a plan and a side view of one wave of the undulatingstorage container 83. Before deep drawing, the sheet metal or plastics panel, of which the storage body is to be made, is corrugated approximately along the seam 91. Thereafter the bulges 92 are made, and then the weld of the two terminal regions along the seam 91 as well as the vertical seams 93. In this region indentations 94 are also provided, by means of which the resilient steel wire 90, which presses the two storage elements 83 and 83 together, is stressed, after positioning the heating element therebetween.

FIG. 10 shows the process steps for the manufacture of a storage insert from one sheet metal or plastics panel only.

FIG. 10a shows the first step, the manufacture of corrugations 101, the regions 102 not being corrugated.

FIG. 10b shows the result of the next process step. The panel as shown in 10a is folded into an undulating shape about the folding axis 103.

FIG. shows the further intermediate step, in which squeezing takes place along the folding axis 105, by means of a prism 104 and a press (not shown) applied from above, whereby the corrugations 101 are squeezed together in the corrugated region 106.

FIG. 10d shows the corrugated region before it is squeezed together on the left, and on the right the corrugated region after it has been squeezed together, the folds 107 at the narrowest point being closely juxtaposed.

FIG. 10e shows the finished insert. Along the folding axis half the panel was folded together and welded along the flanged strip 108 so as to form a seal. The sheet-like heating element 110, which is hermetically sealed into a plastics or sheet metal envelope is inserted between the inwardly directed backs 109, 109. Finally, a lid 110a is put on for closing off the storage body. In this form of the invention, the two opposed folds of the panel form wall members which are oppositely deposed to each other and the opposed depressed portions of the undulated shape form the chamber holding the storage material.

FIG. 11 shows a section through the lid according to FIG. l0e along the section line X-X. The edges of the storage body according to FIG. l0e protrude into the slits 110, whilst the leads 112 are taken through the aperture 111 to the heating element.

I claim:

1. A heat storage container having at least one panel forming a wall of said container, an oppositely disposed wall member of said container, a plurality of chambers formed in part by said panel, a storage material in said chambers which stores heat predominently in the form of heat of crystallization, a plurality of air channels through which ambient air may flow formed in part by said panel, and an electrical resistance element for heating said material during periods of low tariff, characterized in that said heater is in the form of a sheet, in that said panel has a plurality of depressions formed thereon where said depressions extend in the direction and form on one side of the panel a part of said air channels and on the other side of the panel a part of said chambers with the chambers alternating with the air passages, and in that the panel has a flat flanged strip extending along two sides thereof sealingly connected to said oppositely disposed wall member.

2. A heat storage container according to claim 1 further characterized in that said oppositely disposed wall member comprises a second panel and in that the panels are sealingly connected together along their flanged strips and wherein the depressions of each panel are deposed opposite one another to form said chambers holding said storage material;

3. A heat storage container according to claim 2 further characterized in that said heater element is positioned between oppositely deposed depressions of said two panels.

4. A heat storage container according to claim 1 further characterized in that the depressions have undulating side walls.

5. A heat storage container according to claim 1 further characterized in that said panel is folded on itself to form two folds whereby one fold is said oppositely disposed wall member and whereby portions of a single depression are positioned opposite each other to form a chamber for holding said material, and in that portions of the flanged strip on each of the said two sides of said panel are sealingly connected to each other.

6. A heating element for a storage body according to claim 1, characterized in that planar heaters which are insulated on at least one side are uniformly pressed against the storage bodies and in that an elastic mat is provided between the heater and an outside wall or between two heaters for the purpose of compensating for manufacturing tolerances and distortion.

7. A heating element for storage bodies according to claim 6, characterized in that the elastic mat consists of iron filings.

8. A heating element for storage bodies according to claim 7, characterized in that the elastic mat consists of silicon foam rubber.

9. A heating element for storage bodies according to claim 1, characterized in that it is in the form of an elastic plate of low strength, which is subjected to deformation into an undulating line between storage bodies.

10. A heating element for storage bodies according to claim 9, characterized in that the heating body consists of a heat resistant plastics foil, e.g., polyester, to which a conducting layer is applied, e.g., by vapor deposition of aluminum.

11. A heating element for storage bodies according to claim 9, characterized in that one side of every heating body faces the air channel.

12. A heating element for storage bodies according to claim 9, characterized in that separately switchable conducting layers are deposited on the two sides of a heating foil, one conducting strip being disposed in the region between two conducting strips which are disposed on the other side.

13. A heating element for storage bodies according to claim 9, characterized in that high-molecular polyethylene is used for the heating or insulating foil.

14. A storage container according to claim 1, characterized in that the heating body is embedded between two foils which are welded together along their circumference to form an airtight seal. 

2. A heat storage container according to claim 1 further characterized in that said oppositely disposed wall member comprises a second panel and in that the panels are sealingly connected together along their flanged strips and wherein the depressions of each panel are deposed opposite one another to form said chambers holding said storage material;
 3. A heat storage container according to claim 2 further characterized in that said heater element is positioned between oppositely deposed depressions of said two panels.
 4. A heat storage container according to claim 1 further characterized in that the depressions have undulating side walls.
 5. A heat storage container accorDing to claim 1 further characterized in that said panel is folded on itself to form two folds whereby one fold is said oppositely disposed wall member and whereby portions of a single depression are positioned opposite each other to form a chamber for holding said material, and in that portions of the flanged strip on each of the said two sides of said panel are sealingly connected to each other.
 6. A heating element for a storage body according to claim 1, characterized in that planar heaters which are insulated on at least one side are uniformly pressed against the storage bodies and in that an elastic mat is provided between the heater and an outside wall or between two heaters for the purpose of compensating for manufacturing tolerances and distortion.
 7. A heating element for storage bodies according to claim 6, characterized in that the elastic mat consists of iron filings.
 8. A heating element for storage bodies according to claim 7, characterized in that the elastic mat consists of silicon foam rubber.
 9. A heating element for storage bodies according to claim 1, characterized in that it is in the form of an elastic plate of low strength, which is subjected to deformation into an undulating line between storage bodies.
 10. A heating element for storage bodies according to claim 9, characterized in that the heating body consists of a heat resistant plastics foil, e.g., polyester, to which a conducting layer is applied, e.g., by vapor deposition of aluminum.
 11. A heating element for storage bodies according to claim 9, characterized in that one side of every heating body faces the air channel.
 12. A heating element for storage bodies according to claim 9, characterized in that separately switchable conducting layers are deposited on the two sides of a heating foil, one conducting strip being disposed in the region between two conducting strips which are disposed on the other side.
 13. A heating element for storage bodies according to claim 9, characterized in that high-molecular polyethylene is used for the heating or insulating foil.
 14. A storage container according to claim 1, characterized in that the heating body is embedded between two foils which are welded together along their circumference to form an airtight seal. 